When creating and editing computerized images for eventual color printing, a need commonly arises to view the images on an interactive computer display. The interactive display gives the fast response desired for artistic creation, and does not use expensive materials to produce intermediate images to monitor the progression of the creation or editing process. When used in this way, it is desired that the computer display give as accurate a representation as possible to the eventual printed image. This accurate representation has been very difficult because the display and a reflection print are very different media. The display, for example, can reproduce brighter blues and can reproduce a more brilliant image because the display is self luminescent. On the other hand, depending on the materials used, the reflection print can, for example, reproduce deeper reds and aquamarine colors. An image artistically tuned to the strengths of a computer display may not convey the same impact as one tuned to the strengths of a reflection print.
A common approach in the prior art has been to make a "proof", or intermediate test print, at each stage of the process. When used in this way, the artist works creatively from the most recent proof, using the display only to represent changes in a way that the artist's mind is constantly translating back to the proof. There are also different levels of proofs. First quick proofs are made with an ink jet or other inexpensive printer in "proof" mode, then a higher quality proof is made with a slower and more expensive process, such as a dye sublimation printer. Finally, if the image is to be published, a very expensive proof is made using the lithographic system and actual inks with which the final product will be produced. The time and expense of making proofs has always been a major problem to the industry and an impediment to creative freedom of artists.
Accordingly the industry has made efforts to match the image on a computer display with that of the final printed product. Early efforts attempted to achieve a technical match between the measured colors on the display with the measured colors on the print. Because the display is self luminescent and the print is reflective, the two media gave a substantially different artistic feel even when a calibrated meter measured the same numerical color. Further attempts modified the colors by empirically tuning to try to approach the feel of the printed page on the display.
Ultimately all the attempts were limited by differing color gamuts of the display and print media. Color gamut of a media refers to the range of colors the media can reproduce. For example, the color bright spectral blue is within the gamut of the CRT displays, but beyond the gamut of reflection inks which are not very efficient at producing a bright pure blue. The prior art solution in this case was to prevent the display from showing the bright blue color so as to match the limited palette of the print. The problem with this approach is that deep colors, like dark, highly saturated red, yellow, and especially emerald green, can be reproduced with inks but cannot be duplicated on a display. The prior art solution could do nothing besides leaving out those colors also. The result was that the artist was forced to design a medium that was really the worst case of both the display and the final print. The artist either had to have a good imagination of what the final print would look like or choose not to use the print material to its full saturated potential. In addition, the displayed image tended to look "clearer" than the final print because the self luminescent display could show a better distinction among all steps in the gray scale.
As the world moves toward desktop publishing of image-based communication by non-image professionals, the use of expensive and time consuming proofing and skill development to work with the prior art is becoming a serious limit to the advancement of the industry.
With the foregoing in mind, it is readily apparent that an improved system and method were needed to closely replicate all of the available colors and feel of a color printing process on an interactive computer display. In this manner, an editor or artist could work interactively with the image in the computer domain until satisfied that the desired emotional effect had been produced, with the assurance that the image on the screen, by application of the teachings of the invention, would accurately be rendered by the printing process, and furthermore that the full advantages of the printing process colors were included in the interactive creative process.